Removal of V(V) from aqueous Cr(VI)-bearing solution using anion exchange resin: Equilibrium and kinetics in batch studies

Vanadium (V) and chromium (Cr) co-exist in the whole process of V extraction from the vanadium titano-magnetite ore in China. It remains a challenge to remove trace V(V) from Cr(VI) in a simple way. Based on facile pretreatment of transforming Cr(VI) selectively, a novel method to remove V(V) from Cr(VI) by anion exchange resin Dex-V has been established. The influence of operation parameters including pH, contact time and temperature on adsorption ratio has been investigated. The Langmuir model and Henry model were successfully applied to describe the adsorption behavior of V by the Dex-V resin. It is shown that V is adsorbed chemically in monolayer and the Dex-V resin presents a homogeneous nature. Kinetics of V adsorption was analyzed with the pseudo-second order model, the Richenberg model and the Weber-Morris model. Results show that the rate of V adsorption is controlled by film diffusion in initial 70 min and the intra-particle diffusion contributes to the rate-controlling after 70 min. The proposed method was applied to remove V from real waste water and the removal ratio as high as 96% was obtained, with Cr recovery of 95%, which validates the effectiveness and efficiency of the novel method. This work has thus provided new insights into separation and recovery of analog metals in aqueous. (C) 2015 Elsevier B.V. All rights reserved.